The invention relates generally to surface mounted connectors on printed circuit boards, and more specifically, to a flexible contact system for use in socket connectors.
The ongoing trend toward smaller, lighter, and higher performance electrical components and higher density electrical circuits has led to the development of surface mount technology in the design of printed circuit boards. As is well understood in the art, surface mountable packaging allows for the connection of the package to pads on the surface of the circuit board rather than by contacts or pins soldered in plated holes going through the circuit board. Surface mount technology allows for an increased component density on a circuit board, thereby saving space on the circuit board.
The land grid array (LGA) is one type of surface mount package that has developed in response to the demand created by higher density electrical circuits for increased density of electrical connections on the circuit board. The land grid array includes an array of connections on the bottom side of the connector package. In the traditional land grid array connector, stamped and formed contacts having flexible contact beams are soldered to the circuit board using solder balls placed at contact locations on the circuit board.
While LGA technology offers the advantages of higher connection densities on the circuit board and higher package manufacturing yields which lower product cost, LGA technology is not without shortcomings. For instance, the contact beams must be compressed or deflected sufficiently to generate a required normal force on the package to reliably mate the package to the contacts. As a result, the stamped and formed contacts must have sufficient length and working range to generate the required normal force. However, a reduced height contact system is desirable for improved electrical performance.
In a prior art electrical interconnect system as disclosed in U.S. Pat. No. 7,070,420, an array of electrical contacts is held in a substrate. Each contact includes a nonconductive elastomeric element and an associated conductive element. The nonconductive element has opposite ends disposed beyond respective opposite sides of the substrate. The conductive element includes a body having opposite ends disposed exteriorly of respective opposite ends of the nonconductive elastomeric element. The opposite ends of the nonconductive elastomeric element resiliently press against the respective opposite ends of the conductive element when a force is applied to the electrical contact.
A need remains for a compressible contact system having shortened compressive contacts that can be more easily and economically manufactured, and a contact system that improves electrical performance, particularly at higher contact densities.